For different voltage ratings, arresters of this type employ stacks of ceramic discs having stack-lengths that are varied as a direct function of the rated voltage. Typically, this requires that housings of many different lengths be carried in the manufacturer's inventory in order to accommodate the different stack lengths. Substantial cost savings can be achieved if the number of different types of parts required for the housings of the many differently-rated arresters can be reduced.
One way of reducing the number of such parts is to fabricate the housings from pre-formed tubing that can be cut to the desired length and then suitably machined to accommodate end caps, supports, and any other supplemental components required. This approach is unduly labor-intensive and time-consuming, and our invention therefore seeks to avoid it.
Another concern of our invention is that if an arrester should fail during operation, relatively high pressures may be developed within the housing that could cause the housing to rupture. Should such a rupture occur, it is undesirable that live parts of the arrester be expelled from the arrester interior since this could make it more difficult to interrupt the circuit in which the arrester is connected and could cause additional damage to the involved apparatus. It is also undesirable that the ceramic discs be expelled from the housing in the event of a housing rupture.